feat(vscode): allow disabling manifest-derived Qihe args

[hongjr03]

Closes #78.

Adds a VS Code setting to let users opt out of Qihe CLI arguments derived from the Vizsla project manifest.

• add vizsla.qihe.autoConfigureArgsFromManifest, defaulting to true
• keep the current manifest-based behavior by default
• when disabled, stop auto-adding --mode sv and manifest-derived slang args such as --top, -I, and -D
• keep user-provided vizsla.qihe.compileArgs and vizsla.qihe.runArgs as the explicit escape hatch